A technique relating to so-called hot swapping, for example, exchanging, removing, or adding units that constitute a system during operation of the system is known. However, a large current (rush current) may flow through the system when the units are connected during operation of the system and the system may be damaged. Therefore, reducing the rush current has been proposed (e.g., see Patent Document 1 below).
Patent Document 1: Japanese Patent Application Laid-open No. HEI09-284998